The primary objective of this multicenter, randomized, controlled study is to compare the effect of partial liquid ventilation (PLV) with AF0141 (sterile perflubron) to conventional mechanical ventilation on all cause mortality in mechanically ventilated children with acute respiratory distress syndrome. The study population will be comprised of 250 male and female subjects ranging from 36 weeks post-conceptional age to 17 years of age with acute respiratory distress syndrome.